There are many systems available for mounting photovoltaic (PV) modules to building structures, such as a roof. These systems serve as a rigid interconnection element between a roof and a PV module to hold the modules in place and resist the forces of gravity and wind.
Traditionally, mounting systems consisted of rows of rail structures attached to the roof in columns or rows. Module clamps were used to attach the PV modules to these rail structures. Although effective, these traditional systems required complex and time-consuming installations and utilized relatively large amount of materials. Eventually, pioneers in the solar industry, such as Jack West of San Rafael-based Zep Solar, realized that module frames themselves are sufficiently rigid to function as the rails of a PV mounting system. By utilizing the inherent rigidity of modules frames as part of the PV mounting system, system part counts and costs of PV mounting systems were significantly reduced while installation time and overall aesthetics were improved. This realization caused the majority of the residential solar industry to move away from rail-based solutions. However, in order to continue the momentum of solar against other fossil fuel-based energy sources, it is imperative that both hard and soft PV costs continue to be reduced.
Most rail-free or so-called direct mount systems, rely on pillar-like PV module supports which connect to each module frame at various points around the array—typically at least four points on each module. These module supports are in turn attached to the roof, either into a roof rafter or directly to the roof deck, via a flashing. The flashing is just a flat sheet of aluminum with a preformed feature designed to mate with the module support and typically including at least one lag-bolt through-hole for securing both the flashing and the module support to the roof.
Although effective at reducing water leaks and covering missed drill holes, flashings can increase the time of installation because when they are used, the installer must complete all site preparation first before placing any of the PV modules, installing a flashing at each intended roof penetration. This bottleneck prevents an installer from installing the array row-by-row or panel-by-panel and, as a result, may slow-down the rate at which PV can be installed, may require larger installation crews, or both. Also, because each flashing gets tucked underneath the next up-roof course of shingles, it is often necessary to remove existing roofing nails to accommodate the flashings. Each time an existing roofing nail is removed, a new potential leak point is created. Finally, each flashing adds a material cost to each solar installation that becomes significant when multiplied against every roof penetration of every installed array.
Accordingly, there is a need for a rail-free PV mounting system that enjoys the benefits of existing rail-free solutions, while reducing costs, and increasing installation times relative to such systems.